[Elecraft] KPA500 SWR Calibration

[Bob McGraw K4TAX]

Jack, et.al.

Thanks,  Yes I see from the circuit it is not a Breune.   I have 
calibrated the indications for power and all is well in that regard.  I 
just see a higher SWR that actually exists.  That under certain 
conditions causes the amp to fault.   I'll figure a work-a-round and be 
able to deal with it.

73

Bob, K4TAX


On 11/17/2019 10:12 AM, Jack Brindle wrote:
> Bob;
>
> The KPA500 does not use a Breune style bridge, but rather a true directional coupler. It does not need to be nulled; there is no adjustment.
>
> There is an adjustment for the power; see the PWR ADJ setting in the manual.
>
> 73!
> Jack, W6FB
>
>
>> On Nov 17, 2019, at 6:58 AM, Bob McGraw K4TAX <rmcgraw at blomand.net> wrote:
>>
>> I need to null the SWR detector on my KPA500.   I've not found any adjustment procedure as such.   And from the schematic, there is none.
>>
>> I do have a rather precise Bird 50.5 ohm dummy load.  I see SWR values higher than 1:1 on the LED display and also on the LCD display on higher frequency bands.   I've found that the PWR ADJ does affect not only the indicated power but the FAULT values as well.   I am suspect that the  SWR error likewise affects the Fault actions.
>>
>> Any thoughts?
>>
>> 73
>>
>> Bob, K4TAX
>>
>>
>>
>>
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>